The Bacillus Subtilis genome: replication-order and map-position discrepancies--evidence for a second origin

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Replication order discrepancies have been observed in Bacillus subtilis (B. subtilis) genomes.
• These variations occur across different physiological conditions and strains (168 and W23).

Purpose of the Study:

• To investigate the cause of replication order discrepancies in B. subtilis.
• To identify the location of a potential new replication origin.

Main Methods:

• Documenting replication order discrepancies across various physiological conditions and B. subtilis strains.
• Performing detailed linkage analysis of the ura to argA region.

Main Results:

• Replication discrepancies were consistently observed in B. subtilis.
• The earliest replicating markers involved were thr versus purB and aroA versus recA.
• Linkage analysis confirmed the ura to argA region as a continuous linkage group.

Conclusions:

• The findings suggest that replication order discrepancies are a reproducible phenomenon in B. subtilis.
• A new origin for replication initiation has been localized between the recA and aroA genes.